The Human Genetics Center of Indiana Medical School comprises the interdepartmental research, teaching and diagnostic activities of the Department of Medical Genetics, which is now in its tenth year of operation. This proposal requests support for the research activities of the Center. Research will be conducted on Basic Mechanisms in Human Genetics and on Studies of Genetic Disease in Man. Specific research projects will include studies of genetic linkage in man; studies of quantitative inheritance in the half-sib offspring of monozygotic twins; studies of polymorphic salivary proteins; studies of the biochemical evolution of functionally related enzymes; studies of human hexoseaminidase; cytogenetic and clinical studies to delineate new human genetic syndromes; studies of hereditary deafness and a prospective analysis of the effects of genetic counseling. The overall research effort will be coordinated through the establishment of three core laboratories for cytogenetic studies genotyping procedures and research computation. External consultants will assist the principal investigator in program evaluation and planning.